Population Pharmacokinetic Evaluation of Amikacin Liposome Inhalation Suspension in Patients with Treatment-Refractory Nontuberculous Mycobacterial Lung Disease

Background and Objectives: Use of parenteral amikacin to treat refractory nontuberculous mycobacterial (NTM) lung disease is limited by systemic toxicity. A population pharmacokinetic model was developed using data pooled from two randomized trials to evaluate the pharmacokinetic properties of once-daily amikacin liposome inhalation suspension (ALIS) in patients with treatment-refractory NTM lung disease. Methods: In phase 2 (TR02-112) and phase 3 (CONVERT) studies, patients with sputum cultures positive for Mycobacterium avium complex (both studies) or M. abscessus (TR02-112) despite ≥ 6 months of guideline-based therapy were treated with once-daily ALIS 590 mg. Results: Fifty-three patients (28 Japanese; 25 White) were assessed. At baseline and ≈ 6 months after daily dosing, median maximum concentration (C_max) was < 2 mg/L and median area under the concentration-time curve (AUC_0–24) was < 20 mg·h/L, suggesting low systemic exposure at both time points. Exposure estimates were similar between Japanese and White patients. The median unchanged amikacin fraction excreted in urine was < 10% of inhaled dose throughout the TR02-112 study, indicating that relatively small amounts reached systemic circulation. Median t_1/2 was 5.5 h. Amikacin concentrations were much higher in sputum than in serum, demonstrating the ability to achieve higher drug concentration at the site of infection. Median sputum amikacin concentrations in the CONVERT study were high at 1–4 h postdose (range 242–426 μg/g) and decreased by 8 h (median 7 μg/g). Conclusions: Systemic exposure to amikacin in serum and urine following once-daily ALIS administration in patients with treatment-refractory NTM lung disease was notably lower than that previously reported for parenteral amikacin. Trial registration: ClinicalTrials.gov